Research Topics
| PHILIPOS LOIZOUSummaryAffiliation: University of Texas at Dallas Country: USA Publications
Research Grants
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Detail Information
Publications
Comparison of speech processing strategies used in the Clarion implant processorPhilipos C Loizou
Department of Electrical Engineering, University of Texas at Dallas, Richardson 75083 0688, USA
Ear Hear 24:12-9. 2003..To evaluate the performance of the various speech processing strategies supported by the Clarion S-Series implant processor...- Speech processing in vocoder-centric cochlear implantsPhilipos C Loizou
Department of Electrical Engineering, Jonsson School of Engineering and Computer Science, University of Texas at Dallas, Richardson 75083 0688, USA
Adv Otorhinolaryngol 64:109-43. 2006..The various noise suppression strategies proposed over the years based on multi-microphone and single-microphone inputs are also described... 
Tackling the combined effects of reverberation and masking noise using ideal channel selectionOldooz Hazrati
The University of Texas at Dallas, Richardson, TX, USA
J Speech Lang Hear Res 55:500-10. 2012..In this article, a new signal-processing algorithm is proposed and evaluated for the suppression of the combined effects of reverberation and noise...- Extending the articulation index to account for non-linear distortions introduced by noise-suppression algorithmsPhilipos C Loizou
Department of Electrical Engineering, University of Texas at Dallas Richardson, TX 75083 0688, USA
J Acoust Soc Am 130:986-95. 2011..9) was obtained with the proposed measure when evaluated with intelligibility scores obtained by normal-hearing listeners in 72 noisy conditions involving noise-suppressed speech corrupted in four different real-world maskers... - Speech recognition by bilateral cochlear implant users in a cocktail-party settingPhilipos C Loizou
Department of Electrical Engineering, University of Texas at Dallas, Richardson, Texas 75083 0688, USA
J Acoust Soc Am 125:372-83. 2009..Furthermore, the use of noise interferers does not adequately reflect the difficulties experienced by bilateral users in real-life situations... - On the number of channels needed to understand speechP C Loizou
Department of Electrical Engineering, University of Texas at Dallas, Richardson 75083 0688, USA
J Acoust Soc Am 106:2097-103. 1999..The findings of experiment 2 suggest an inverse relationship between the importance of spectral amplitude resolution (number of steps) and spectral resolution (number of channels)... - Subspace algorithms for noise reduction in cochlear implantsPhilipos C Loizou
Department of Electrical Engineering, University of Texas at Dallas, Richardson, Texas 75083 0688, USA
J Acoust Soc Am 118:2791-3. 2005..Further work is needed to extend the subspace algorithm to nonstationary noise environments... - Dichotic speech recognition in noise using reduced spectral cuesPhilipos C Loizou
Department of Electrical Engineering, University of Texas at Dallas, P O Box 830688, EC 33, Richardson, Texas 75083 0688, USA
J Acoust Soc Am 114:475-83. 2003..Sentences presented dichotically in the odd-even frequency condition were identified more accurately than when presented in the low-high condition... - Speech recognition by normal-hearing and cochlear implant listeners as a function of intensity resolutionP C Loizou
Department of Electrical Engineering, University of Texas at Dallas, Richardson 75083 0688, USA
J Acoust Soc Am 108:2377-87. 2000.... - The effect of parametric variations of cochlear implant processors on speech understandingP C Loizou
Department of Electrical Engineering, University of Texas at Dallas, Richardson 75083 0688, USA
J Acoust Soc Am 108:790-802. 2000..The above results indicate that audiologists can optimize the implant listener's performance either by increasing the pulse rate or by jointly varying the pulse rate and pulse width... - Minimum spectral contrast needed for vowel identification by normal hearing and cochlear implant listenersP C Loizou
Department of Electrical Engineering, University of Texas at Dallas, Richardson 75083 0688, USA
J Acoust Soc Am 110:1619-27. 2001.... - Factors affecting masking release in cochlear-implant vocoded speechNing Li
Department of Electrical Engineering, University of Texas at Dallas, Richardson, Texas 75083 0688, USA
J Acoust Soc Am 126:338-46. 2009..This outcome suggests that having access to the acoustic landmarks provided by the obstruent consonants enables listeners to integrate effectively pieces of the message glimpsed over temporal gaps into one coherent speech stream... - Environment-specific noise suppression for improved speech intelligibility by cochlear implant usersYi Hu
Department of Electrical Engineering, University of Texas Dallas, Richardson, Texas 75080, USA
J Acoust Soc Am 127:3689-95. 2010..The present study demonstrated that the environment-specific approach to noise reduction has the potential to restore speech intelligibility in noise to a level near to that attained in quiet... - The contribution of obstruent consonants and acoustic landmarks to speech recognition in noiseNing Li
Department of Electrical Engineering, University of Texas at Dallas, Richardson, Texas 75083 0688, USA
J Acoust Soc Am 124:3947. 2008..These landmarks, often blurred in noisy conditions, are critically important for understanding speech in noise for better determination of the syllable structure and word boundaries... - An algorithm that improves speech intelligibility in noise for normal-hearing listenersGibak Kim
Department of Electrical Engineering, University of Texas at Dallas, Richardson, TX 75080, USA
J Acoust Soc Am 126:1486-94. 2009..The findings from this study suggest that algorithms that can estimate reliably the SNR in each T-F unit can improve speech intelligibility... - Use of a sigmoidal-shaped function for noise attenuation in cochlear implantsYi Hu
Department of Electrical Engineering, University of Texas at Dallas, Richardson, Texas 75083 0688, USA
J Acoust Soc Am 122:EL128-34. 2007..Much of the success of the proposed noise reduction algorithm is attributed to the improved temporal envelope contrast... - Selective-tap blind signal processing for speech separationKostas Kokkinakis
Center for Robust Speech Systems, Department of Electrical Engineering, University of Texas at Dallas, Richardson, TX 75080, USA
Conf Proc IEEE Eng Med Biol Soc 2009:3150-3. 2009.... - Using blind source separation techniques to improve speech recognition in bilateral cochlear implant patientsKostas Kokkinakis
Department of Electrical Engineering, The University of Texas at Dallas, Richardson, Texas 75080, USA
J Acoust Soc Am 123:2379-90. 2008.... - Contribution of consonant landmarks to speech recognition in simulated acoustic-electric hearingFei Chen
Department of Electrical Engineering, The University of Texas at Dallas, Richardson, Texas, USA
Ear Hear 31:259-67. 2010..As a secondary objective, this study examines the performance of an objective measure that can potentially be used for predicting the intelligibility of vocoded speech... 
Real-time automatic switching between noise suppression algorithms for deployment in cochlear implantsVanishree Gopalakrishna
Department of Electrical Engineering, University of Texas at Dallas, Richardson, TX 75080, USA
Conf Proc IEEE Eng Med Biol Soc 2010:863-6. 2010..The results obtained indicate the feasibility of this on-the-fly switching for actual deployment in cochlear implants...- The intelligibility of speech with "holes" in the spectrumKalyan Kasturi
Department of Electrical Engineering, University of Texas at Dallas, Richardson 75083-0688, USA
J Acoust Soc Am 112:1102-11. 2002..For vowels, there was unequal weighting across the various channels, while for consonants the frequency-importance function was relatively flat, suggesting that all bands contributed equally to consonant identification... - The influence of noise on vowel and consonant cuesGaurang Parikh
Department of Electrical Engineering, University of Texas at Dallas, Richardson, Texas 75083-0688, USA
J Acoust Soc Am 118:3874-88. 2005..Stop consonant recognition remained high even at -5 dB despite the disruption of burst cues due to additive noise, suggesting that listeners must be relying on other cues, perhaps formant transitions, to identify stops... - A recursive wavelet-based strategy for real-time cochlear implant speech processing on PDA platformsVanishree Gopalakrishna
Department of Electrical Engineering, University of Texas at Dallas, Richardson, TX 75080, USA
IEEE Trans Biomed Eng 57:2053-63. 2010..In addition, it is shown that this strategy leads to a lower amount of spectral leakage. The PDA implementation is made interactive to allow users to easily manipulate the parameters involved and study their effects... - A phone-assistive device based on Bluetooth technology for cochlear implant usersHaifeng Qian
Department of Electrical Engineering. University of Texas at Dallas, Richardson, TX 75083-0688, USA
IEEE Trans Neural Syst Rehabil Eng 11:282-7. 2003..A hardware prototype was built and software programs were written to implement the headset profile in the Bluetooth specification. Three cochlear implant users were tested with the proposed phone-adapter and reported good speech quality... - Factors influencing glimpsing of speech in noiseNing Li
Department of Electrical Engineering, University of Texas at Dallas, Richardson, Texas 75083 0688, USA
J Acoust Soc Am 122:1165-72. 2007.... - Effects of electrode design and configuration on channel interactionsGinger S Stickney
University of Texas at Dallas, School of Human Development, Box 830688, Richardson, TX 75083 0688, USA
Hear Res 211:33-45. 2006.... - A new sound coding strategy for suppressing noise in cochlear implantsYi Hu
Department of Electrical Engineering, University of Texas at Dallas, Richardson, Texas 75083 0688, USA
J Acoust Soc Am 124:498-509. 2008..Overall, the findings from the present study suggest that the SNR criterion is an effective selection criterion for n-of-m strategies with the potential of restoring speech intelligibility... - Use of S-shaped input-output functions for noise suppression in cochlear implantsKalyan Kasturi
Department of Electrical Engineering, University of Texas at Dallas, Richardson, TX 75083 0688, USA
Ear Hear 28:402-11. 2007..The aim of this study is to assess the influence of the shape of the acoustic-to-electric mapping function on speech recognition in noise by cochlear implant listeners... - A glimpsing account for the benefit of simulated combined acoustic and electric hearingNing Li
Department of Electrical Engineering, University of Texas at Dallas, Richardson, Texas 75083 0688, USA
J Acoust Soc Am 123:2287-94. 2008..These findings taken together suggest that a significant factor contributing to the EAS advantage is the enhanced ability to glimpse the target... - A comparative intelligibility study of single-microphone noise reduction algorithmsYi Hu
The University of Texas at Dallas, Department of Electrical Engineering, P O Box 830688, Richardson, Texas 75083, USA
J Acoust Soc Am 122:1777. 2007..Overall, the analysis of consonant confusion matrices suggests that in order for noise reduction algorithms to improve speech intelligibility, they need to improve the place and manner feature scores... - Factors influencing intelligibility of ideal binary-masked speech: implications for noise reductionNing Li
Department of Electrical Engineering, University of Texas at Dallas, Richardson, Texas 75083 0688, USA
J Acoust Soc Am 123:1673-82. 2008..This pattern directs the listener's attention to where the target is and enables them to segregate speech effectively in multitalker environments... - Effect of filter spacing on melody recognition: acoustic and electric hearingKalyan Kasturi
Department of Electrical Engineering, University of Texas at Dallas, Richardson, Texas 75083 0688, USA
J Acoust Soc Am 122:EL29-34. 2007..The quality of melodies processed by the semitone filter spacing was preferred over melodies processed by the conventional logarithmic filter spacing... - Simulating the effect of spread of excitation in cochlear implantsMohamed Bingabr
Department of Engineering and Physics, University of Central Oklahoma, 100 North University Drive, Edmond, OK 73034, USA
Hear Res 241:73-9. 2008..This outcome is partly consistent with behavioral data obtained with cochlear implant studies in that CI users tend to do as well or better with monopolar stimulation than with bipolar stimulation... - Music perception by cochlear implant and normal hearing listeners as measured by the Montreal Battery for Evaluation of AmusiaWilliam B Cooper
Callier Advanced Hearing Research Center, The University at Dallas, Dallas, TX, USA
Ear Hear 29:618-26. 2008..Ann N Y Acad Sci, 999, 58-75) to assess the music perception abilities of cochlear implant (CI) users... - Effect of spectral resolution on the intelligibility of ideal binary masked speechNing Li
J Acoust Soc Am 123:EL59-64. 2008..Results from Experiment 2 indicated that having access to the ideal binary mask in the F1/F2 region is sufficient for good performance... - A comparison of the speech understanding provided by acoustic models of fixed-channel and channel-picking signal processors for cochlear implantsMichael F Dorman
Department of Speech and Hearing Science, Arizona State University, Tempe 85287 0102, USA
J Speech Lang Hear Res 45:783-8. 2002..Both strategies are capable of providing a very high level of speech recognition. Choosing between the two strategies may, ultimately, depend on issues that are independent of speech recognition-such as ease of device programming... - Acoustic simulations of combined electric and acoustic hearing (EAS)Michael F Dorman
Department of Speech and Hearing Science, Arizona State University, Tempe, Arizona 85287-0102, USA
Ear Hear 26:371-80. 2005..However, performance levels will be maximized if the gap between acoustic and electric stimulation is minimized... - Factors that allow a high level of speech understanding by patients fit with cochlear implantsMichael F Dorman
Department of Speech and Hearing Science, Arizona State University, Tempe 85287 0102, USA
Am J Audiol 11:119-23. 2002..Third, perceiving strategies for speech are inherently flexible in terms of the mapping between signal frequencies (i.e., the locations of the formants) and phonetic identity...
Research Grants
- SIGNAL PROCESSING STRATEGIES FOR COCHLEAR PROSTHESISPHILIPOS LOIZOU; Fiscal Year: 2003..Most importantly, it will open new avenues for the development of future signal processing strategies for cochlear prosthesis. ..
- Optimizing speech coding strategies for noise and musicPHILIPOS LOIZOU; Fiscal Year: 2009....
- Optimizing speech coding strategies for noise and musicPHILIPOS LOIZOU; Fiscal Year: 2007....
- User customization and user optimization of cochlear implant devicesPhilipos C Loizou; Fiscal Year: 2010....